1. Field of the Invention
The present invention relates to a multi-layer molding method by which the mold apparatus can be made compact.
2. Description of the Related Art
In the field of resin moldings, there is provided a resin molding product in which a second layer, the resin material of which is different from that of a base layer, is locally formed on the base layer. In general, this type molding product is produced by the multi-layer molding method and referred to as a multi-layer molding product.
Conventionally, in the above multi-layer molding method, there is used a mold apparatus 9 including two core molds 91, 92, a mold 93 for the base layer and a mold 94 for the second layer as shown in FIG. 13. Molding is conducted with this mold apparatus as follows. For example, this type mold apparatus is disclosed in Japanese Patent Publication No. Sho. 59-199227.
First, the base layer 81 is molded by one core mold 91 and the mold 93 for the base layer. Next, the core mold 91 is turned downward in a direction of an arrow E as shown in FIG. 13, and the second layer 82 is locally molded on the base layer 81 by the core mold 91 and the mold 94 for the second layer.
In the process of molding described above, molding of the base layer 81, which is conducted by one core mold 91 and the mold 93 for the base layer, and molding of the second layer 82, which is conducted by the other core mold 92 and the mold 94 for the second layer, are simultaneously executed. The core molds 91, 92 are turned and used successively for the molding as described above. In this connection, reference numeral 96 shown in the drawing is a plunger used for the injection of resin.
However, in the above conventional multi-layer molding method, it is necessary to provide four molds in total including the two core molds 91, 92, the mold 93 for the base layer, which is opposed to the core mold, and the mold 94 for the second layer, wherein the mold 93 for the base layer and the mold 94 for the second layer are respectively opposed to the two core molds 91, 92. Also, it is necessary to provide a space and a drive unit for turning the core molds 91, 92.
Therefore, the size of the apparatus is increased, and further it becomes necessary to provide a large space for turning the molds. Accordingly, the productivity is low and the equipment cost is high.